Abating sinker for circular knitting machines



March 13, 1962 R. TENCONI 3,024,634

ABATING SINKER FOR CIRCULAR KNITTING MACHINES Filed Dec. 15, 1960 States ate 3,024,634 ABATING SINKER FOR CIRCULAR KNITTING MACHINE Unite The present invention relates to circular knitting machines and more particularly is directed to an improved type of abating sinker for circular machines for the manufacture of stockings and socks.

As is well-known, the main members of those machines which cooperate for the formation of the loops are the needles and the sinkers. Generally tongued needles are used which are arranged in the longitudinal slits of the needle-cylinder while the sinkers constituted by shaped steel plaques are arranged in as many radial slits of the sinker-ring rigid with the needle-cylinder. While the needles are controlled by the cams of the cam-assembly to effect rising and descending movements the sinkers are controlled to effect radial movements synchronized with the movements of the needles.

Various types of sinkers are known which have different shapes; all of them however generally have a beak. a throat formed by that beak and, in front of the throat, the abating plane.

An inconvenience encountered during the formation of the loop with those conventional sinkers consists in that the length of the individual loop heads is not accurately constant if said heads are formed by the needle in front of the beak of the sinker at the abating plane since in that case there is no accurate control of the length of the loop head which may vary according to the tension of the knitted fabric previously formed.

To avoid the above disadvantage it has been proposed to form the loop head with the needle in back of the beak of the sinker rather than in front of the beak. In such case it is necessary to use special sinkers which have a small extension behind the beak for abating. In that case, the length of the loop head i determined by the distance between the center of the throat, of the sinker, which retains the previously knitted fabric and the axis of the needle when the latter descends to make the new thread pass through the loop head previously formed. That method of forming loop heads which are accurately uniform and calibrated (Kleer Kit system) has given good results, however it has the inconvenience that it does not allow beginning of the work, namely the formation of the first course of the knitted fabric, without having to resort to particular contrivances which considerably complicate operation of the knitting machine and require supplemental members for changing the method of loop formation at the start of the fabric. In fact, in order to be able to form the first course, it is necessary to form the loop head in front of the beak of the sinker in order that the latter may be able to retain the loop head at a time when previously knit fabric is not available.

The present invention provides a sinker that eliminates the above mentioned inconvenience and permits attainment of the main object of forming uniform and calibrated loop heads without having to modify the remaining control members already existing in the circular knitting machines and without having to resort to any supplemental members.

The above objects are attained according to the invention by providing an abating sinker which, in addition to its normal beak, has a second or supplemental beak disposed at a short distance before the normal beak.

By reason of the above configuration of the sinkers, the

0 ice movements of the needles and of the sinkers can always be the same, that is, during the initial looping and during the subsequent formation of the knitted fabric.

The normal beak of the sinker embodying the invention is active only during forming of the first course and functions to prevent the needle from dragging the formed loop head upwards. With respect to that normal beak of the sinker, the needle works in the usual way, that is to say, in front of the normal beak.

During formation of the remainder of the fabric, the supplemental beak is active and the needle works behind said supplemental beak which has the function of calibrating accurately the length of each loop head that is formed.

The invention will be more fully [understood by reference to the following detailed description of an illustrative embodiment thereof which is to be read in connection with the accompanying drawing, wherein:

FIG. 1 is a side elevational view of a sinker of conventional type;

FIG. 2 is a side elevational view of a sinker according to the invention;

FIGS. 39 diagrammatically illustrate the successive stages of formation of the loops beginning with the initial looping; and FIG. 10 is a developed sectional view taken along the line X-X on FIG. 9, and showing the cooperative relationship of several needles and sinkers.

The conventional type of sinker P illustrated in FIG. 1 is a generally blade-like or laminar member which comprises a beak 1, a throat 2, the abating plane 3, the nose 4, the body 5, the heel 6 and an abutment 7 for the spring (not shown) that surrounds all of the sinkers in the sinker-ring.

The same identical parts are found also in the sinker P according to the invention which, as shown in FIG. 2, is further provided with a second beak 8 disposed before the usual beak 1 and with a corresponding second throat 9.

The formation of the loop with the sinker according to the invention takes place in the following manner:

At the beginning of looping the needle 10 with its tongue 11 open rises (FIG. 3) to take the thread 12 by its hook 13. The sinker P is disposed in its radially inward position.

The needle that has gripped the thread 12 descends (FIG. 4) and simultaneously the sinker moves radially outward sufliciently so that the thread is made to rest between the two beaks 1 and 8 of the sinker. Then the needle rises again (FIG. 5) and the beak 1 retains the thread 12 in throat 2 thus preventing the upward movement of the thread as happens with the normal sinkers.

When the needle has reached the end of its upward stroke (FIG. 6), the sinker again moves radially inward and the thread 12 passes over the front beak 8.

Now the needle descends again with its book gripping and dragging along the new thread 12a (FIG. 7), and simultaneously the sinker moves radially outward so that a the new thread 12a is laid between the two beaks 1 and 8 while the old previously formed loop of thread 12 is retained by the throat 9 of the beak 8 ('FIG. 8).

[Finally the needle rises again (FIG. 9) While the sinker is still in its radially outward position, so that the throat 9 of its front beak 8 retains the formed loop head which in that way is very accurately calibrated, as is shown in FIG. 10. The rear beak 1 of the sinker remains inactive during the remainder of the loop-formation.

As has been seen the invention achieves the desired uniformity in the loop heads in an extremely simple manner and does not require anything but the replacement in the existing knitting machine of conventional sinkers by sinkers having two beaks. All of the remaining control parts and parts actuating the needles and sinkers in the circular knitting machine have not been referred to in detail in the present description because the same are known to those skilled in the art, and need not be varied from those in common knitting machines.

The adoption of the sinker according to the present invention does not affect the possibility of varying at will the length of the loop heads, which variation is obtained, as is well-known, by displacing the needle-cylinder upwards or downwards. The greater the upward displacement of the cylinder, the greater will be the length of the loop heads that are formed. However, in order to ensure that such a variation of length would not be annulled by the calibration achieved with the sinkers according to the invention, it is necessary that, upon the displacement of the needle-cylinder for varying the length of the loop heads, there should be eifected also a displacement in the radial direction of the sinker-controlling cam. More specifically, when the cylinder is displaced upward to make the loop heads longer, the cam for controlling the sinkers should be simultaneously displaced radially inward to permit the sinkers to be moved a greater distance radially outward during the calibrating stage (see FIGS. 7 to 9). On the other hand, upon displacement of the needle-cylinder downward, there will have to be eifected a corresponding radially outward displacement of the cam for controlling the sinkers. The members that effect such displacements of the sinker-controlling cam in accordance with the displacement of the cylinder, may be very simple, for instance levers or the like, and it is believed unnecessary to describe a particular embodiment thereof.

I claim:

An abating sinker for circular knitting machines particularly adapted for the manufacture of hosiery; said sinker comprising a laminar body having a first beak defining a first throat and an abating plane, and a second beak at a short distance from said first beak and defining a second throat.

Lieberknect May 22, 1934 Miller Aug. 16, 1938 

